Treatment of textile fibers



United States Patent TREATMENT OF TEXTILE FIBERS Elmer Rossin,Springfield, Mass., assignor to Monsanto Chemical Company, St. Louis,Mo., a corporation of Delaware No Drawing. On'ginal application December1, 1949, Serial No. 130,603, now Patent No. 2,730,790, dated January 17,1956. Divided and this application June 7, 1955, Serial No. 513,910

6 Claims. (Cl. 117-139.5)

The present invention relates to the treatment of textile fibers priorto spinning for the purposes, among others, of improving the inter-fiberfriction of such fibers and increasing the tensile strength of the yarnresulting from the further processing and the eventual spinning of thefibers.

It is one object of the present invention to provide an improved methodof treating textile fibers prior to spinning to produce fibers havingincreased inter-fiber friction and other improved properties and whichare readily spun into yarns of high tensile strength and at the sametime avoid the formation of sticky fibers or the generation of excessiveamounts of fly during the manipulation of such fibers prior to andduring spinning.

Still further objects and advantages of this invention will appear fromthe following description and the appended claims.

This invention is carried out, in general, by applying to textile fibersat some stage of their processing prior to spinning, an aqueousdispersion of fine, discrete, unagglomerated particles of a hard,non-plasticized, waterinsoluble, polymerized thermoplastic resin whichis substantially resistant to plasticization with water and isnonfilm-forming at temperatures below 150 F. The dispersion is suppliedto the fibers in an amount suflicient to deposit from 0.1 to 3% byWeight of the resin and not more than 40% by weight of water, both basedon the weight of the fibers. The fibers are then allowed to dry whilethey are further processed and without heating the fibers.

The dispersion may contain anionic surface active agents since thedispersions employed in this invention are prepared in most instances bythe emulsion polymerization of suitable unsaturated organic compounds inthe presence of anionic surface active agents. The dispersions should,however, be free of cationic surface active agents which cause the resinto exhaust onto the fibers since the resin first agglomerates and thenexhausts on the fibers resulting in the deposition of large, nonuniformparticles on the fibers. The dispersions should also be free ofmultivalent metals which also render the resin substantive, and shouldalso be free of agents which agglomerate or coagulate the resinparticles. Anionic surface active agents are preferably used in thedispersion to assist the penetration of the dispersion through the fibermass.

As examples of textile fibers which are treated in accordance with themethods of the present invention may be mentioned wool fibers, cottonfibers, mixtures of wool and cotton fibers, synthetic staple fibers suchas staple fibers prepared from regenerated cellulose, cellulose esters,cellulose ethers, synthetic linear polyamides, polyacrylonitrile,copolymers of vinyl chloride and vinyl acetate and the like or mixturesof such synthetic staple fibers withcotton and/or wool; or such naturalfibers as linen, flax and the like. The preferred fibers are wool orcotton or mixtures thereof.

The aqueous dispersions employed in accordance with.

Patented Nov. 4, 1958 2. A this invention may be prepared in a varietyof ways provided the dispersion is sufliciently stable to permit itsapplication to the fibers without settling or agglomeration of the resinparticles therein and providing also that it is substantially free ofcationic surface active agents, multivalent metals and resinagglomerating agents. Such dispersions are known in the resin art andare commercially available. A satisfactory method for preparingdispersions or suspensions in the case of resins which cannot beprepared by emulsion polymerization involves dispersing extremely finelydivided resin particles in water with the aid of an anionic surfaceactive agent by mixing in a high speed stirrer, a colloid mill or ahomogenizer. This result may also be achieved by mixing such ingredientsin a ball mill until the resin particles remain suspended.

A preferred method for forming the aqueous dispersions is to polymerizein an aqueous emulsion suitable gaseous or liquid monomeric unsaturatedorganic compounds which when sufiiciently polymerized are'hard andWater-insoluble materials and are also non-filmfo ing when dried at roomtemperature. Polymerization of such monomericcompounds in an aqueousemulsionis generally carried out by first dispersing the monomers nwater with an anionic surface active agent to form an aqueous emulsionand then heating the resulting emulsion either in the presence orabsence of a polymerization catalyst. The polymerization may also becarried out at room temperature or even lower temperatures in thepresence of actinic radiation and/or a polymerization catalyst. Gaseousmonomers can be emulsion polymerized in a low pressure autoclave.

As examples of monomeric substances whichare useful in the preparationof the aqueous dispersions by emulsion polymerization techniques may bementioned styrene; vinyl chloride; nuclear substituted chloro-styrene;acrylonitrile; vinylidene chloride; or combinations of one or more ofthese monomers with divinylbenzene; mixtures of styrene, vinyl chlorideor vinylidene chloride and fumaro-nitrile or acrylonitrile; mixtures offrom to 99% by weight of styrene or chloro-styrene and from 20 to 1% byweight of butadiene or isoprene; mixtures of from 80 to 99% by weight ofstyrene, chloro-styrene, vinyl chloride or vinylidene chlorideand from20 to 1% by weight of alkyl acrylates .containing from 1 to 4 carbonatoms in the alkyl group, alkyl methacrylates containing from 1 to 4carbon atoms in the alkyl'group or mono or dialkyl esters of maleic orfuman'c acid containing-from 1 to 6 carbon atoms in the alkyl group;

mixtures of from to 99% by weight of vinyl chloride and from 15 to 1% byweight of vinyl acetate; and mixtures of from 65 to 99% by weight ofstyrene, chlorostyrene, vinyl chloride or vinylidene chloride and from35 to 1% by weight of methyl acrylate, methyl methacrylate or dimethylmaleate. Improvedhardness and resistance to plasticization by water canbe obtained by using a cross-linking agent such as divinyl benzene. Theabove list is not exhaustive since any gaseous or liquid monomericunsaturated compounds which polymerize in an aqueous emulsion to formaqueous dispersions of fine, discrete, unagglomerated particles of ahard, waterinsoluble, non-plasticized thermoplastic resinwhi'ch isnon-film-forming and non-plasticizable by wateninay also be used.

Aqueous dispersions prepared by the emulsion polymerization of styreneare preferred for use in the'methods of this invention because they giveexcellent results and are cheap and readily available. These dispersionsand the dispersions prepared from the monomeric unsaturated compoundsdescribed above should be substantially free of monomers, however, sincethe monomers tend .to plas- V ably'between 10 and 55% by Weight. largelydependent on the nature of the textile fiber being or even'film-forming.Such monomers can be kept at a minimum by carrying the polymerization tosubstantial completion, forexample, by increasing thepolymerization"'time or" by distilling off the monomers.

Polymers or'copolymers' produced fromany ofthe combinations ofunsaturated compounds mentioned above may'be polymerizediin other waysor coagulated after emulsion polymerization and then ground up intoextremely fine particles and dispersed mechanically in themanner'hereinb'efore described to form suitable aqueous dispersions. I

' As examples of anionic surface active agents which are "useful. inpreparing emulsion polymers of the type described above or which areuseful for dispersing finely divided thermoplastic resins suitable forthe preparation of thaqueous dispersions may be mentioned water-solublealkalirmetal salts of saturated and unsaturated fatty acids'containing10 or more carbon atoms, water-soluble alkali metal salts of alkylatednaphthalene sulfonic acids iorqof alkylated benzene sulfonic acids,water-soluble alkali metal salts of sulfated or sulfonated fattyalcohols containing" 10 or more carbon atoms or the like.

i The aqueous dispersions employed in this invention ,generally'have 'apH between about '5 and 8 depending upon" the materials used in theirpreparation and the conditions under which they are prepared. However,it is alsopossible to use dispersions having a higher pH than 8 *o'ra'lower pH than 5; For example, wool may be ftreated without'appreciableloss in tensile strength with Taeidic or mildly alkaline dispersionswhile cotton and other cellulosic materials do not show any appreciable:loss in strength when alkaline or mildly acidic dispersions 'areemployed. Some synthetic staple fibers, for example,

cellulose acetate or'polyamides. may require treatment with neutral orsubstantially neutral dispersions. "The resin concentration of theaqueous dispersions is "generally between 0.5 and 70% by weight andprefer- This factor is treated. For example, in the case of cellulosicfibers .such as cotton'fibers and regenerated cellulose fibers best.results are obtained when a minimum of water is added to thefibers withthe resins. In such instances when 0.1

153% by weight, based on the weight of the fibers, of

resin is applied,v the amount of water applied is not in -excess .of 6%by weight on the weight of the fibers. This -.means, normally, that theaqueous dispersions should not contain less than about 33% .by weight ofresin for the application of 3 by weight of resin on the fibers and not'less'than 2% by weight resin for the application of 0.1%

by weight resin on the fibers.

Wool'fibers and similar animal fibers, on the other lhan'd, can bewetted with larger amounts of water than cotton and regeneratedcellulose fibers without interfering with the manipulativecharacteristics of the fibers.

Thus animal fibers which are processed in the Woolen system or in theBradford or French systems can tolerate the addition of up to about 35%by weight and in f'some'instances up to 40% 'by weight of water, basedon the weight of fibers. with from 15 to 20% by weight of water and withfrom "5 to 10% by weight of oil, both percentages being based onthe'fiber weight, during the processing of such fibers.

Normally, wool fibers are treated 'In accordance with the presentinvention the water normally applied with the wool oil is supplied tothe fibers by using the aqueous dispersion of the resin per se or byusing such dispersion and additional quantities of water, if suchadditional quantities of water are necessary. In those instances when0.1 to 3% by weight of .resin, based on the weight of the wool fibers,is applied, Ithe amount of water applied is, preferably, in the range offrom 5 to 20% by weight based on the weight of the fibers, althoughlarger amounts as high as 40% by weight may be used. This means,normally, that the aqueous dispersion preferably contains not less thanabout weight resin and 5% by weight water on the fibers, the

aqueous dispersion preferably contains not less than 2% by weight resin,or when it is desired to apply 0.1% by weight resin and 20% by weight ofwater, the aqueous dispersion preferably contains not less than 0.5% byWeight resin.

The amount of water which can be applied with the resin to other fibers,for example, synthetic staple 'fibers such as linear polyamide staplefibers, cellulose ester staple fibers, cellulose ether staple fibers orthe like is generally the same as in the case of cotton fibers or isintermediate between the amount applied to cotton fibers andwool'fibers.

It is thus seen that the resin is applied to the textile fibers inamounts of 0.1 to 3% by weight, based onthe weight of 'the fibers, andthat the amount of water applied with the resin is'up to 40% by weight,based on the weight of the fibers, depending upon the particular fiberwhich is being processed. Again, the resin concentration of the aqueousdispersions varies between 0.5 and 60% by weight depending onthe amountof resin ap plied to the fibers and the particular fiber being treated.

The aqueous dispersions hereinbefore defined may 'be applied to textilefibers at any stage'of their processing prior to spinning. .In the caseof wool and other animal fibers which are processed according to thewool system it is preferred to apply the aqueous dispersions to the woolfibers just prior to the blending box. Application is generally made byspraying or sprinkling the dispersion on the fibers until the desiredamount of resin and water has been applied. Since oil is normally addedto the wool fibers, the oil may be incorporated in the dispersion andapplied therewith or it maybe added separately. The aqueous dispersionis "preferably applied to wool fibers or other animal fibers, which arebeing processed in the Bradford or French systems, at the gill box wherethe fibers are formed into a sliver. Here the dispersions are applied,for example, by dripping the dispersion on' the fibers or by means ofthe normal squirrel cage applicator the dispersions on thefibersuntilthe desired amount of In those instances resin and water hasbeen applied. y when the fibers are treated after carding but before theformation of the fully condensed sliver, the dispersions may be appliedin various ways. For example, one mode of procedure consists in firstforming a partiallycondensed web of the carded fibers as they move fromthe card, which Web is thin and' generally rectangular in cross section,and then spraying the dispersion in finely dividedform on oppositesides'and to the same part of the web as itmoves in a vertical plane.

Another mode -of procedure is to apply the dispersion to the interiorportion'of the sliver by means of an applicator device as the web or'carded fibers is condensed in a customary trumpet, *Thisjapplicator deviceincludes a hollow tube which is positioned in the trumpet in such amanner that it is substantially coincident with the center' of thetrumpet and parallel tothe'direction of movement of the fiberspassingthrough thetnnnpet, the orifice of the hollow tube terminatinginsidethetrumpet and closely adjacent to theorifice of the trumpet; andalso" includes At the first three of the above-named locameans forsupplying a liquid to the hollow tube. The aqueous dispersion issupplied to the hollow tube by gravity flow and the dispersion is wipedfrom the orifice of the tube, as it drips therefrom, by the fibers asthey move past the tube on their way through the orifice of the trumpet.The dispersion is thus deposited in the center portion of the sliver asthe sliver is formed in the trumpet. The amount of resin and waterdeposited is regulated by the rate at which the sliver is formed, therate of flow of the dispersion through the hollow tube, and the resinconcentration of the. dispersion. The procedure and apparatus used inthis mode of operation are described in greater detail in the patent toSiever, No. 2,115,218.

The textile fibers which have been treated with resin and water in theamounts hereinbefore descibed, are further processed in the normalmanner and without being dried. This is an important advantage in thatno extra equipment, outside of the spraying equipment or otherapplication equipment used in applying the dispersions, is required.Also, by dispensing with the drying of the fibers it is possible toprocess the fibers at lower cost and without the danger of softening theresin which softening often results in the formation of neps or otherlumps which interfere with the processing of the fibers and cause anincreased number of ends down. By using fine, discrete, unagglomeratedparticles of a hard, non-plasticized, water-insoluble, polymerized resinwhich is non-film-forming and hydrophobic, it is possible to obtainimproved slip resistance, spin the fibers into yarn at a lower twistmultiple or to speed up the rate of production without the formation ofappreciable amounts of neps or other lumps of fibers and withoutappreciably increasing the normal number of ends down.

The yarns produced in accordance with the methods of the presentinvention contain from 0.1 to 3% by weight of fine, discrete,substantially unagglomerated particles of a hard, non-plasticized,water-insoluble, polymerized thermoplastic resin. The resin particlesare distributed throughout the length of the yarn. These yarns arecharacterized by increased tensile strength at normal twist multiples orby normal tensile strength at lower twist multiples than can normally beused and in the latter case are softer and fuller than yarns preparedwithout the addition of such resin. They are further characterized inthat they are relatively free of neps and by the fact that the fiberstherein are not bound together by the resin and are free of resin film.

A further understanding of the present invention will be obtained fromthe following specific examples which are intended to be illustrative ofthe invention but not limitative of the scope thereof, parts andpercentages being by weight unless otherwise specified.

Example I An aqueous dispersion of polystyrene resin was first preparedas follows:

Forty parts of monomeric styrene, 0.1 part of K S O as a catalyst, 12parts of the sodium salt of dodecyl benzene sulfonic acid as anemulsifying agent, 0.07 part of sodium dihydrogen phosphate and 0.28part of disodiurn hydrogen phosphate as buffering agents, and 58.2 partsof water were first agitated to form an emulsion. The emulsion was thenheated at a temperature between 90 and 95 C. for 2 hours under a refluxcondenser and :then cooled'rapidly to room temperature. The resultingdispersion contained 40% by weight of fine discrete, un- :agglomeratedparticles of hard, water-insoluble and nonplasticized polystyrene resinwhich was non-film-forming when placed on a watch glass and allowed todry at room temperature. The dispersion also contained about 0.3% byweight of free monomer. The pH of the dispersion was between 7.0 and 7.5as measured by indicator paper.

The above dispersion was diluted with water until it containedpolystyrene solids. This dispersion was then applied to a webof 1%; inchregenerated cellulose (viscose) staple fibers, as the web was beingcondensed into a sliver, by means of a hollow tube which was in sertedinto the central portion of the sliver as it was formed in such a waythat the dispersion was taken up by the fibers by a wiping action as thesliver passed by the tube. The type of apparatus and the method ofapplication employed are described in detail in U. S. Patent No.2,115,218, hereinbefore referred to. The dispersion was supplied to thehollow tube in an amount suflicient to provide 0.25% polystyrene resinand 2.5% water, both based on the weight of the fibers in the sliver,and throughout the entire length of the sliver. i

The resulting sliver was drawn twice and then made into a roving in thenormal manner. .During the drawing the sliver exhibited a considerablyincreased resistance to slippage, indicating that the inter-fiberfriction had been increased by the resin treatment. To compensate forthis increased resistance to slippage the drawing was conducted byopening up the drawing roll settings.

A control roving was prepared from 1% inch regenerated cellulose(viscose) staple fiber in the normal manner and without the resintreatment.

The treated roving and control rovings were then tested for break factorwith the following results:

The treated roving gave no difiiculty during spinning and enabled thespinning of a yarn having good tensile strength at reduced twistmultiple.

Example 11 An aqueous dispersion of polystyrene resin was first preparedas described in Example I and was then diluted with water until itcontained 5% polystyrene solids. This dispersion was then mixed with aself-emulsifiable wool oil, the wool oil being added in amountssufficient to equal the weight of polystyrene in the dispersion. Theresulting dispersion was sprayed in the form of finely divided dropletson clothing wool fibers in the blending box in an amount suflicient todeposit 0.5% of polystyrene particles, 0.5% of the wool oil and 10% ofwater, all percentages being based on the weight of the fibers. Thefibers were then processed into wool yarns according to the wool systemof processing and spinning. The fibers were processed withoutdifiiculty, but did exhibit an increased drag or resistance to slippageduring the processing operations. The resulting yarn was relatively freeof neps or lumps of fibers and the processing machinery showed noevidence of resin accumulation.

Control yarns were prepared from clothing wool in the same manner exceptthat no polystyrene resin was used.

The treated and control yarns were tested for tensile strength with thefollowing results:

Example III An aqueous dispersion containing 15% by weight of fine,discrete, unagglomerated particles of a hard, nonplasticized,water-insoluble, polyvinyl chloride which is substantially resistant toplasticization with water and non-'film-forming at temperatures below150 F., prepared by the emulsion polymerization of vinyl chloride, andabout 1.5% of decyl benzene sodium sulfonate as a dispersing agent wassprayed in the form of fine droplets on 1 inch Strict Middling cotton atthe cotton picker hopper. The dispersion was supplied in an amountsuificient to deposit 0.75% polyvinyl chloride particles and 5.0% water,both percentages based on the Weight of the fibers. The treated fiberswere made into laps, and then carded, drawn and roved on regular millequipment. In order to spin the roving into yarn it was necessary toreduce the normal roving twist by 20%.

The roving was spun into s, 20s and 30s yarns which had appreciably moretensile strength than similar yarns prepared from the same cotton fibersbut which were not treated with resin.

The aqueous dispersions employed in accordance with the presentinvention may be modified by the addition of textile conditioning agentsother than the anionic surface active agentsor oils heretoforedescribed. Thus it is possible to add small amounts, i. e., 0.1 to 5% byweight of softening agents, humectants, hygroscopic agents, lubricants,non-ionic surface active agents and the like providing, of course, thatsuch agents are not cationic surface agents or agglomerating agents ordo not plasticize the thermoplastic resin particles.

This is a division of my .co-pending application Serial No. 130,603,filed December 1, 1949, now U. S. Patent No. 2,730,790, granted January17, 1956.

What is claimed is: g

1. A spun textile yarn containing wool fibers and from 0.1% to 3% byweight, based on the weight of fibers in the yarn, of fine, discrete,substantially unagglomerated particles of a'hard non-plasticizedwater-insoluble polymerized thermoplastic resin derived from monomericunsaturated organic compounds, said resin being substantially free ofmonomers, said yarn being further characterized in that the fiberstherein are not bound together by the resin and are free of resin film.

.2. A spun textile yarn containing from 0.1 to 3% by Weight, based onthe weight of fibers in the yarn, of fine, discrete, substantiallyunagglomerated particles of a'hard, non-plasticized, water-insolublepolymerized thermoplastic resin derived from monomeric, unsaturatedorganic compounds, said resin being substantially free of monomers, saidyarn being further characterized in that the fibers therein are notbound together by the resin and are free of resin film.

3. A spun textile yarn as in claim 2, but further char acterized in thatsaid resin is polystyrene.

4. A spun textile yarn as in claim 2, but further characterized in thatsaid resin is polyvinyl chloride.

5. A spun textile yarn as in claim 2, but further characterized in thatsaid resin is a copolymer of a mixture of from to 99% styrene and 20' to1% of an alkyl maleate containing from 1 to 6 carbon atoms in the alkylgroup.

6. Unspun textile fibers containing from 0.1 to 3% by weight, based onthe weight of fibers, of fine, discrete,

substantially unagglomerated particles of a hard, nonplasticized,water-insoluble polymerized thermoplastic resin derived from monomeric,unsaturated organic compounds, said resin being substantially free ofmonomers, said fibers being further characterized in that they are notbound together by the resin and are free of resin film.

References Cited in the file of this patent UNITED STATES PATENTS1,983,349 Dreyfus Dec. 4, 1934 2,054,131 Kollek Sept. 15, 1936 2,350,032Hager May 30, 1944 2,436,614 Sparks et al Feb. 24, 1948 2,511,593Lightfoot -3 June 13, 1950 2,534,315 Swanson l Dec. 19, 1950 2,534,318Swanson Dec. 19, 1950 2,570,750 Bauer Oct. 9, 1951 2,610,927 FouldsSept. 16, 1952

2. A SPUN TEXTILE YARN CONTAINING FROM 0.1 TO 3% BY WEIGHT, BASED ON THEWEIGHT OF FIBERS IN THE YARN, OF FINE, DISCRETE, SUBSTANTIALLYUNAGGLOMERATED PARTICLES OF A HARD, NON-PLASTICIZED, WATER-INSOLUBLEPOLYMERIZED THERMOPLASTIC RESIN DERIVED FROM MONOMERIC, UNSATURATEDORGANIC COMPOUNDS, SAID RESIN BEING SUBSTANTIALLY FREE OF MONOMERS, SAIDYARN BEING FURTHER CHARACTERIZED IN THAT THE FIBERS THEREIN ARE NOTBOUND TOGETHER BY THE RESIN AND ARE FREE OF RESIN FILM.